As the damage of the direct and indirect environmental pollution related to the industry continues, environment friendly methods and environmental pollution prevention technologies are attracting attention, and techniques for adsorbing or stabilizing various environmental pollutants are actively studied. In particular, it has been found that heavy metal substances of environmental pollutants inhibit or interfere with essential chemical action of cells or biomaterials (biomolecules) present in the body, and pose a fatal risk to biochemical function of biological species through action of modifying or damaging properties of biomembranes in the body. The risk of these heavy metal substances can be confirmed through the case of itai-itai disease caused by cadmium intoxication and the case of Minamata disease caused by mercury intoxication.
Heavy metal vapor such as mercury that can be discharged into the atmosphere is mostly generated during coal combustion, but while the incineration scale of urban and medical wastes increases in recent years, the generation amount increases. In addition, in order to improve safety and efficiency in the natural gas process, it is necessary to efficiently remove the heavy metal vapor. Natural gas contains up to 200 ppbv of mercury, which does not only lead to severe corrosion of heat exchangers and metal surfaces during the processes, but also poses a risk that natural gas process operators may be exposed to high concentrations of mercury, and results in a problem of accelerating poisoning phenomena of high-priced metal catalysts, such as platinum and palladium, in the process.
Ion exchange, chemical precipitation, electrochemical (electrolytic) methods, and the like are progressing as methods for removing such heavy metal materials. However, these methods have drawbacks such as economical disadvantages in equipment and operation, a process problem due to complicated steps in the process, and low abatement efficiency in low concentration heavy metal materials. The removal of heavy metal materials using adsorbents has been studied for performance as an adsorbent for various materials because of advantages showing process convenience, economical efficiency, and high removal efficiency even in low concentration heavy metal materials.
In addition, attempts have been made to improve desorption of heavy metal materials using chemical adsorption by impregnating sulfur of chalcogen elements. However, there is a problem that results in lifetime reduction due to decrease of carbon fiber pores by the impregnation of liquid sulfur and increase of emission matter amounts in the manufacturing process.
In this regard, Korean Laid-Open Patent Publication No. 2008-0013629 disclosed a method of coating functional nanoparticles on the surface of an activated carbon fiber filter, but did not provide an alternative to the above problem.